Pulse generating and counting circuit with disabling means



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Jan.- 17, 1967 J. GIACCHI PULSE GENERATING AND COUNTING CIRCUIT I WITHDISABLING MEANS Filed Sept. 8, 1964 o l :o

INVENTOR. JOHN GIACCHI WW -M COUNTER United States Patent 3,299,313PULSE GENERATING AND COUNTING CIRCUIT WITH DISABLING MEANS John Giacchi,Somerville, N.J., assignor to Burroughs Corporation, Detroit, Mich., acorporation of Michigan Filed Sept. 8, 1964, Ser. No. 394,971 12 Claims.(Cl. 315-85) This invention relates to pulse-generating circuits and,particularly, to a programmable circuit for automatically generating aseries of groups of pulses, with the number of pulses in each groupbeing variable and controllable.

The objects of the present invention concern the provision of animproved automatic and controllably variable pulse-generating circuitwhich is stable, utilizes its pulsegenerating capabilities to themaximum, and has efiicient, automatic turn-off means.

Briefly, the circuit of the invention includes a multi-positionmagnetron beam switching tube which is coupled to a multivibratordriver. The beam switching tube and the driver are .coupled together insuch a way that, when an electron beam is formed in the tube, it turnson the multivibrator. The multivibrator runs freely and drives the beamswitching tube to switch an electron beam from position to position. Themultivibrator and the beam switching tube are so related that, when anelectron beam reaches a predetermined last position and the lastpossible pulse has been generated, then the beam switching tube and themultivibrator are automatically turned off. The

circuit of the invention includes an efiicient arrangement forautomatically turning off the beam switching tube at the end of apulse-generating cycle while allowing the tube to generate an outputpulse from each of its positions.

The invention is described in greater detail by reference to the singlefigure of the drawing which is a schematic representation of a circuitembodying the invention.

Referring to the drawing, the circuit of the invention includes a'multi-position magnetron beam switching tube 16, preferably of the typeknown as a BeamX switch, which is coupled to a multivibrator driver 18.The device 16 is well known in the art and includes ten positions orgroups of electrodes, from each of which an output pulse may beobtained. Each group of electrodes includes a target or output electrode20, a spade electrode 24 which forms and holds an electron beam on itsassociated tar-get electrode, a switching electrode 28 which may be usedto switch an electron beam from one position to the next, and a shieldelectrode 32. The spade electrodes 24 may also be employed to perform abeam switching function. A magnetron beam switching tube also includes acathode 36 and permanent magnet means (not shown) for providing amagnetic field which operates with the electric fields in the tube tocontrol the movement of an electron beam therein. In the drawing, forpurposes of simplification, the switching electrodes 28 are shownschematically at one end of the tube envelope, rather than in each groupof electrodes.

In the circuit 10 and referring to tube 16, each spade electrode 24 isprovided with a signal input terminal 38 and is coupled through acapacitor 40 to ground. Each spade electrode 24 is also coupled througha load resistor 46 to a common spaced bus 48 which is coupled to apositive DC. power supply V1. In addition, according to the invention,the spade electrode at the last position, the 9 position in tube 16,includes in its load circuit a diode 50, oriented as shown, inserted inseries with its spade load resistor 46. The cathode of diode 50 iscoupled through a bias resistor 52 to spade bus 48. A capacitor 56 isconnected between the anode of the diode 50 and a portion of themultivibrator 18, to be described below. Another diode 60, oriented asshown, is connected between the anode of the first diode 50 and thespade bus 48.

. "ice The target or output electrodes 20 of tube 16 are connected insets, with the tar-gets at the even-numbered positions being connectedin one set and to a bus 62, and the targets at the odd-numberedpositions being connected in a set and to a bus 66. One end of the bus62 is coupled through a resistive path both to the switching electrodes28 at the even-numbered positions and to power source V3, and one end ofthe bus 66 is connected through a resistive path both to the switchingelectrodes 28 at the odd-numbered positions and to power source V3. Theother end of each bus 62 and 66 is connected through a separatecapacitor 70 to ground.

The cathode 36 of tube 16 is connected through a parallel combination ofresistor 74 and capacitor 78 to ground. Cathode 36 is also coupled tomultivibrator 1-8 in a manner to be described below. The shieldelectrodes 32 are connected to a suitable positive DC. power source V2.

The multivibrator 18 may be of generally conventional form and may bemade up of two transistors or two tubes,

\ as desired. In the drawing, the multivibrator is shown as comprisingtwo tubes 78 and 80 having cathodes 82 and 84, control grids 88 and 90,and anodes 94 and 96, respectively. The cathode electrodes 82 and 84 areconnected together and through a resistive path to ground, and theanodes and control grids are capacitively crossconnected. The anode 94is used to operate a suitable utilization device, for example, amechanical counter 100, which includes a mechanical relay 102 to whichthe anode 94 is connected through a resistive path. This resistive pathis also coupled to a bus 104 which is coupled to a DC. power source V3.The. anode 94 is also coupled through lead 106 to capacitor 56 and thusto the junction of diodes 50 and 60. The anode 96 is connected through aresistive path to bus 104 and through capacitors 108 to botheven-numbered and odd-numbered switching electrodes 28 in tube 16. Eachset of switching electrodes 28 is also connected through a resistivepath to ground.

The control grid is coupled through separate resistive paths to the bus104 and to ground. The control grid 88- is connected through resistor108 and lead 110 to the cathode 36 of tube 16.

The operation of the pulse generator circuit 10 is as follows. Thecircuit is adjusted so that initially the beam switching tube 16 doesnot have an electron beam formed therein, and, in the multivibrator,tube 78 is off and tube 80 is on. This condition is maintained by theapplication of ground potential from the cathode 36 of tube 16 throughlead 110 to the grid 88 of tube 78 of the multivibrator. When it isdesired to set the circuit in operation and generate a series of pulses,a negative start pulse is applied to one of the spade electrodes 24 intube 16, say the 0 spade, through its input terminal 38. This pulseapplied to the 0 spade causes an electron beam to form and flow from thecathode 36 to the 0 position in tube 16, and the cathode 36 rises inpotential to a positive level which is transmitted through lead 110 tothe grid 88 of tube 78 of the multivibrator. The multivibrator is nowrendered operative and runs freely in known fashion. With each completecycle of operation of the multivibrator, and, particularly, each timethat tube 80 turns on and its anode 96 goes negative in potential, acount is registered in the counter and the beam is moved by one positionin the beam switching tube 16.

When finally the electron beam reaches the last position or position 9in tube 16, the beam is cleared due to the action of the load circuitconnected to the 9 spade. When the electron beam is thus cleared, thecathode 36 of tube 16 drops to about ground potential, and thispotential transmitted through lead to the grid 88 of tube 78 againdisables the multivibrator .18, and the initial conditions are restoredin the multivibrator, with tube 80 being on and tube 78 being off. Thus,one cycle of operation is completed.

The aforementioned beam clearing circuit operates as follows. As themultivibrator executes a cycle of operation, anode 94 and its outputpath are pulsed alternately in positive and negative directions. Thesepositive and negative potential pulses are coupled through the lead 106to the junction of diodes 50 and 60. At the same time, anode 96 and itsoutput path assume potentials opposite to those of anode 94- and itsoutput path. This mode of operation of a multivibrator is well known. Asthe multivibrator switches an electron beam from position to position inbeam tube 16, but before the beam reaches the 9 position, when apositive pulse appears at anode 94 and on lead 106, this positive pulsepasses through diode 60 and out through the low impedance power supplyV1 without affecting the potential of the 9 spade. When a negative pulseappears at the junction of the diodes 50 and 60, and whether a beam ispresent or not in the 9 position, the 9 spade is not affected.

When the beam is in the 8 position, the next negative pulse appearing atanode 96 and on its output lead is coupled to the switching grids 28 andcauses the beam to switch to the 9 position. At the same time, the anode94 and its output lead are pulsed positively. However, this positivepulse, coupled through lead 106 to the load circuit of the 9 spade, isdissipated before the beam forms and locks in the 9 position. Thus, thispositive pulse does not affect the switching of an electron beam intothe 9 position. The next change in state of the multivibrator appliespositive potential to anode 96 and negative potential to anode 94. Thechange in state of the multivibrator has no effect on the beam or on theload circuit of the 9 spade. However, the next change in state of themultivibrator provides a negative pulse from anode 96 and a positivepulse from anode 94. The latter positive pulse, coupled through lead106, acts to clear the electron beam from position 9 before it has anopportunity to switch to the next position. The positive pulse producedby anode 94 is applied at the junction of the diodes 50 and 60 andbiases diode 50 in the forward direction. This causes the 9 spade to beraised to a positive potential at which it cannot support an electronbeam, and the beam is cleared.

In the next and successive cycles of operation, if it is desired toprovide a different number of output pulses, then the electron beam isset at some position other than the 0 position in tube 28 by theapplication of a pulse at the proper terminal 38. After the beam hasthus been set at the desired position, the required number of pulses isgenerated in the manner described above, with each position of the tube16 being usable in the pulse-generating process.

The circuit of the invention thus provides an improved arrangement forobtaining groups of pulses, with the number of pulses in each groupbeing variable and adjustable. The circuit provides a relatively simpleand effic-ient arrangement for, in effect, turning itself on and turningitself otf. The circuit also permits full utilization of each positionin the magnetron beam switching tube used as the control means in thecircuit.

It is to be understood that various modifications may be made in thecircuit shown within the scope of the invention. For example, asmentioned above, the multivibrator might be made up of any known type ofsemiconductor device. In addition, any utilization device other than acounter might be used to register or display the pulses generated duringoperation of the circuit.

What is claimed is:

1. A pulse-generating circuit including a multivibrator and amulti-position beam switching tube connected together as apulse-generating module,

the multivibrator including (1) electrode control means for holding itoff or free-running and (2) output means for transmitting outputthereby,

the output means of said multivibrator being coupled to utilizationmeans for receiving output pulses and to said beam switching tubewhereby each pulse is registered both in said utilization means and insaid beam switching tube,

said electrode control means of said multivibrator also being coupled tosaid beam switching tube whereby the state of operation of saidmultivibrator, that is whether it is off or free-running, is controlledby the state of said beam switching tube, and

auxiliary circuit means coupled between the output of said multivibratorand one position in said beam switching tube for automatically clearinga beam therein and thus ending a pulse-generating cycle and disablingsaid multivibrator.

2. The circuit defined in claim 1 wherein said auxiliary circuit meansincludes a connection from the spade electrode at said one positionthrough a pair of diodes connected anode-to-anode to a power source, theoutput of said multivibrator being connected through a capacitor to thejunction of said pair of diodes, said spade electrode also being coupledthrough a load resistor to said power supply.

3. The circuit defined in claim 1 wherein said auxiliary circuit meansincludes a connection from the spade electrode at said one positionthrough a pair of diodes connected anode-to-anode to a power source, theoutput of said multivibrator being connected through a capacitor to thejunction of said pair of diodes, said spade electrode also being coupledthrough a load resistor to said power pp y.

and an auxiliary resistor connected between the junction of said pair ofdiodes and said power supply.

4. The circuit defined in claim 1 wherein said beam switching tubeincludes an electron-emitting cathode and a plurality of groups ofelectrodes 'in operative relation therewith whereby an electron beam canflow from said cathode to one of said groups of electrodes,

said electrode control means of said multivibrator also being coupled toan electrode in said beam switching tube whereby the state of operationof said multivibrator is controlled by the presence or absence of anelectron beam in said beam switching tube.

5. The circuit defined in claim 1 wherein said beam switching tubeincludes an electron-emitting cathode and a plurality of groups ofelectrodes in operative relation therewith and adapted to receive anelectron beam from said cathode, said electrode control means of saidmultivibrator being coupled to said cathode so that when an electronbeam is formed in said beam switching tube and flows from said cathodeto a group of electrode means, the multivibrator changes from the offstate to the free-running state and thus generates a group of pulses,said means automatically ending a pulse-generating cycle coupled betweenthe output of said multivibrator and the one position in said beamswitching tube for extinguishing an electron beam therein and thusdisabling said multivibrator. 6. A pulse generating circuit including amultivibrator and a multi-position beam switching tube connectedtogether as a pulse-operating module,

said multivibrator including two separate discharge devices, each havinga control electrode and an output electrode and adapted to be held intwo states (1) a free-running state and (2) an off state,

said beam switching tube including an electron-emitting cathode and aplurality of groups of electrodes in operative relation therewith andadapted to receive an electron beam from said cathode, each group ofelectrodes including a target electrode for receiving pulses generatedan electron beam, a spade electrode for forming and holding a beam onits associated target electrode, and a switching electrode for switchingan electron beam from one position to another,

one control electrode of said multivibrator being coupled to the cathodeof said beam switching tube so that when an electron beam is formed insaid beam switching tube and flows from said cathode to one group ofelectrodes therein, the multivibrator is switched from the off state tothe free-running state and thus generates a group of pulses,

one output of said multivibrator being coupled to said switchingelectrodes of said beam switching tube to cause an electron beam toswitch from one position to the next with each cycle of operation ofsaid multivibrator as it runs free,

auxiliary circuit means coupled between the other output of saidmultivibrator and the spade electrode at one position in said beamswitching tube for extinguishing an electron beam therein after theselected group of pulses has been generated, the extinguishing of theelectron beam also disabling said multivibrator, and

setting-selection means coupled to each of the spade electrodes in saidbeam switching tube for selecting the group of electrodes at which anelectron beam will form and thus controlling the number of pulsesgenerated in a group.

7. The circuit defined in claim 6 wherein said auxiliary circuit meansincludes a connection from the spade electrode at said one positionthrough a pair of diodes connected anode-to-anode to a power source, oneoutput of said multivibrator being connected through a capacitor to thejunction of said pair of diodes to couple positive and negative pulsesalternately thereto, said spade electrode also being coupled through aload resistor to said power supply.

8. The circuit defined in claim 6 wherein said auxiliary circuit meansincludes a connection from the spade electrode at said one positionthrough a pair of diodes connected anode-to-anode to a power source, theoutput of said multivibrator being connected through a capacitor to thejunction of said pair of diodes to couple positive and negative pulsesalternately thereto, said spade electrode also being coupled through aload resistor to said power supply,

and an auxiliary resistor connected between the junction of said pair ofdiodes and said power supply.

9. A pulse generator circuit including a pulse source having an inputcircuit and an output circuit and including a control electrode whichpermits the pulse source to be held in two states, one state in which itis disabled and does not generate pulses, or a second state in which itis free-running and generates pulses,

a multi-position pulse counting circuit which is adapted to be held intwo states, one state in which it is energized and can receive and countpulses from said pulse source, or a second state in which it isdisabled, said pulse source also being disabled, at the same time,

first means in said counting circuit for energizing it,

a first connection between said pulse counting circuit and said pulsesource for rendering said pulse source free-running when the countingcircuit is energized, or disabling said pulse source when said countingcircuit is disabled,

said counting circuit being coupled to the output of said pulse sourceand including electrode means for registering the receipt of pulsesserially in its positions starting at the first or some intermediateposition and terminating at the last position,

second means in said counting circuit for selecting a position at whichits counting operation is to start,

disabling circuit means at the last position in said pulsecountingcircuit for disabling it when the pulse count reaches said lastposition, and

a second connection from the output of said pulse source to saiddisabling circuit means at said last position in said pulse countingcircuit for operating said disabling circuit and thus disabling saidpulse counting circuit and said pulse source when the pulse countreaches said last position.

10. The circuit defined in claim 9 wherein said disabling circuitincludes a pair of diodes connected in series between said last positionof said counting circuit and a source of bias voltage, and the junctionof said diodes is capacitively coupled to said second connection fromthe output of said pulse source.

11. The circuit defined in claim 9 wherein said first means and saidsecond means comprise electrode means for forming an electron beam anddirecting it to the selected position at which the counting operation isto start, and

said counting circuit includes means in its coupling to the output ofsaid pulse source for receiving pulses therefrom and moving the electronbeam from one position to the next with each pulse received.

12. The circuit defined in claim 9 wherein said first means and saidsecond means comprise electrode means for forming an electron beam anddirecting it to the selected position at which the counting operation isto start,

said counting circuit includes, in its coupling to the output of saidpulse source, means for receiving pulses therefrom and moving theelectron beam from one position to the next with each pulse received,and

said disabling circuit includes a pair of diodes connected in seriesbetween said last position of said counting circuit and a source of biasvoltage, and the junction of said diodes is capacitively coupled to saidsecond connection from the output of said pulse source.

References Cited by the Examiner UNITED STATES PATENTS 2,856,558 10/1958Cola 315- 3,002,151 9/1961 Broderick et al 328-496 3,158,854 11/1964Keen et al. 3158.5 X

JAMES W. LAWRENCE, Primary Examiner.

R. SEGAL, Assistant Examiner.

9. A PULSE GENERATOR CIRCUIT INCLUDING A PULSE SOURCE HAVING AN INPUT CIRCUIT AND AN OUTPUT CIRCUIT AND INCLUDING A CONTROL ELECTRODE WHICH PERMITS THE PULSE SOURCE TO BE HELD IN TWO STATES, ONE STATE IN WHICH IT IS DISABLED AND DOES NOT GENERATE PULSES, OR A SECOND STATE IN WHICH IT IS FREE-RUNNING AND GENERATES PULSES, A MULTI-POSITION PULSE COUNTING CIRCUIT WHICH IS ADAPTED TO BE HELD IN TWO STATES, ONE STATE IN WHICH IT IS ENERGIZED AND CAN RECEIVE AND COUNT PULSES FROM SAID PULSE SOURCE, OR A SECOND STATE IN WHICH IT IS DISABLED, SAID PULSE SOURCE ALSO BEING DISABLED, AT THE SAME TIME, FIRST MEANS IN SAID COUNTING CIRCUIT FOR ENERGIZING IT, A FIRST CONNECTION BETWEEN SAID PULSE COUNTING CIRCUIT AND SAID PULSE SOURCE FOR RENDERING SAID PULSE SOURCE FREE-RUNNING WHEN THE COUNTING CIRCUIT IS ENERGIZED, OR DISABLING SAID PULSE SOURCE WHEN SAID COUNTING CIRCUIT IS DISABLED, SAID COUNTING CIRCUIT BEING COUPLED TO THE OUTPUT OF SAID PULSE SOURCE AND INCLUDING ELECTRODE MEANS FOR REGISTERING THE RECEIPT OF PULSES SERIALLY IN ITS POSITIONS STARTING AT THE FIRST OR SOME INTERMEDIATE POSITION AND TERMINATING AT THE LAST POSITION, SECOND MEANS IN SAID COUNTING CIRCUIT FOR SELECTING A POSITION AT WHICH ITS COUNTING OPERATION IS TO START, DISABLING CIRCUIT MEANS AT THE LAST POSITION IN SAID PULSECOUNTING CIRCUIT FOR DISABLING IT WHEN THE PULSE COUNT REACHES SAID LAST POSITION, AND A SECOND CONNECTION FROM THE OUTPUT OF SAID PULSE SOURCE TO SAID DISABLING CIRCUIT MEANS AT SAID LAST POSITION IN SAID PULSE COUNTING CIRCUIT FOR OPERATING SAID DISABLING CIRCUIT AND THUS DISABLING SAID PULSE COUNTING CIRCUIT AND SAID PULSE SOURCE WHEN THE PULSE COUNT REACHES SAID LAST POSITION. 